/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/* Some ICMP messages should be passed to the transport protocols. This
   is not implemented. */

#include "lwip/opt.h"

#include "lwip/icmp.h"
#include "lwip/inet.h"
#include "lwip/ip.h"
#include "lwip/def.h"

#include "lwip/stats.h"


void
icmp_input(struct pbuf *p, struct netif *inp)
{
        u8_t type;
        struct icmp_echo_hdr *iecho;
        struct ip_hdr *iphdr;
        struct ip_addr tmpaddr;

#ifdef ICMP_STATS
        ++lwip_stats.icmp.recv;
#endif /* ICMP_STATS */

        /* TODO: check length before accessing payload! */

        type = ((u8_t *)p->payload)[0];

        switch (type)
        {
        case ICMP6_ECHO:
                LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));

                if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
                        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));

                        pbuf_free(p);
#ifdef ICMP_STATS
                        ++lwip_stats.icmp.lenerr;
#endif /* ICMP_STATS */

                        return;
                }
                iecho = p->payload;
                iphdr = (struct ip_hdr *)((u8_t *)p->payload - IP_HLEN);
                if (inet_chksum_pbuf(p) != 0) {
                        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo (%"X16_F")\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len)));

#ifdef ICMP_STATS
                        ++lwip_stats.icmp.chkerr;
#endif /* ICMP_STATS */
                        /*      return;*/
                }
                LWIP_DEBUGF(ICMP_DEBUG, ("icmp: p->len %"S16_F" p->tot_len %"S16_F"\n", p->len, p->tot_len));
                ip_addr_set(&tmpaddr, &(iphdr->src));
                ip_addr_set(&(iphdr->src), &(iphdr->dest));
                ip_addr_set(&(iphdr->dest), &tmpaddr);
                iecho->type = ICMP6_ER;
                /* adjust the checksum */
                if (iecho->chksum >= htons(0xffff - (ICMP6_ECHO << 8))) {
                        iecho->chksum += htons(ICMP6_ECHO << 8) + 1;
                } else {
                        iecho->chksum += htons(ICMP6_ECHO << 8);
                }
                LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo (%"X16_F")\n", inet_chksum_pseudo(p, &(iphdr->src), &(iphdr->dest), IP_PROTO_ICMP, p->tot_len)));
#ifdef ICMP_STATS
                ++lwip_stats.icmp.xmit;
#endif /* ICMP_STATS */

                /*    LWIP_DEBUGF("icmp: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len);*/
                ip_output_if (p, &(iphdr->src), IP_HDRINCL,
                              iphdr->hoplim, IP_PROTO_ICMP, inp);
                break;
        default:
                LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" not supported.\n", (s16_t)type));
#ifdef ICMP_STATS
                ++lwip_stats.icmp.proterr;
                ++lwip_stats.icmp.drop;
#endif /* ICMP_STATS */
        }

        pbuf_free(p);
}

void
icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
{
        struct pbuf *q;
        struct ip_hdr *iphdr;
        struct icmp_dur_hdr *idur;

        q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
        /* ICMP header + IP header + 8 bytes of data */

        iphdr = p->payload;

        idur = q->payload;
        idur->type = (u8_t)ICMP6_DUR;
        idur->icode = (u8_t)t;

        memcpy((u8_t *)q->payload + 8, p->payload, IP_HLEN + 8);

        /* calculate checksum */
        idur->chksum = 0;
        idur->chksum = inet_chksum(idur, q->len);
#ifdef ICMP_STATS
        ++lwip_stats.icmp.xmit;
#endif /* ICMP_STATS */

        ip_output(q, NULL,
                  (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
        pbuf_free(q);
}

void
icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
{
        struct pbuf *q;
        struct ip_hdr *iphdr;
        struct icmp_te_hdr *tehdr;

        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded\n"));

        q = pbuf_alloc(PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);

        iphdr = p->payload;

        tehdr = q->payload;
        tehdr->type = (u8_t)ICMP6_TE;
        tehdr->icode = (u8_t)t;

        /* copy fields from original packet */
        memcpy((u8_t *)q->payload + 8, (u8_t *)p->payload, IP_HLEN + 8);

        /* calculate checksum */
        tehdr->chksum = 0;
        tehdr->chksum = inet_chksum(tehdr, q->len);
#ifdef ICMP_STATS
        ++lwip_stats.icmp.xmit;
#endif /* ICMP_STATS */
        ip_output(q, NULL,
                  (struct ip_addr *)&(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
        pbuf_free(q);
}








